This invention relates to a zeolite carrier, to a method of preparing same, to a hydrogenation catalyst using same and to a process for hydrocracking a heavy oil using such a catalyst.
One known catalyst for hydrocracking heavy oils uses a solid acid carrier, such as silica-alumina or alumina-boria, for supporting a hydrogenation catalytic metal. The known catalyst has problems because a high reaction temperature of at least 420xc2x0 C. and a high hydrogen partial pressure are required to perform hydrocracking. Further, the catalytic metal must be used in a large amount to obtain satisfactory hydrocracking efficiency. To cope with this problem, a catalyst having a catalytic metal supported on a zeolite carrier and exhibiting high hydrogenation activity has been proposed. This catalyst, however, poses a problem of catalyst poisoning when used for the hydrocracking of an asphaltene-containing heavy oil and is ill-suited for industrial scale application.
It is an object of the present invention to provide a composite zeolite material which can uniformly support catalytically active metal components for various reactions and which can efficiently exhibit its acid function.
Another object of the present invention is to provide a catalyst which can exhibit hydrogenation activities such as hydrocracking, hydrodesulfurization and hydrodenitrification activities.
It is a further object of the present invention to provide a catalyst of the above-mentioned type suitable for hydrocracking an asphaltene-containing heavy oils.
In accomplishing the above problems, the present invention provides a catalyst support comprising a zeolite having an Al/Si atomic ratio of 0.01-0.1 and mesopores having a pore diameter in the range of 5-30 nm, and ultrafine particles composited to inside walls of the mesopores, said superfine particles being an oxide of a metal selected from the group consisting of Ti, Zr and Hf.
In another aspect, the present invention provides a catalyst having a catalytic metal having hydrogenation activity and supported on the above catalyst support.
The present invention further provides a method of preparing the above catalyst support, which includes the steps of:
(a) contacting a zeolite with a solution having a pH of 0.8-2 and containing a salt of a metal selected from the group consisting of Ti, Zr and Hf, said zeolite having an Al/Si atomic ratio of 0.01-0.35 and mesopores having a pore diameter in the range of 5-30 nm and accounting for at least 10% by volume of a total pore volume thereof, so that a hydroxide of said metal deposits on inside walls of the mesopores with the simultaneous reduction of the Al/Si atomic ratio;
(b) then washing and drying said metal hydroxide-bearing zeolite; and
(c) then calcining said dried zeolite at 400-600xc2x0 C. to convert the metal hydroxide into metal oxide.
The present invention also provides a process for hydrocracking a heavy oil comprising subjecting the heavy oil to hydrocracking conditions in the presence of the above catalyst.